Authors have to (MUST) spend as much time marketing their books as writing them.
Use the time between submission of your manuscript and the actual publication of the book to market the book and build a community of potential readers.
Traditional bookstore appearances and signings can be expensive and don’t work as well as getting sponsors to buy your book in bulk in return for a free speech.
Good luck and don’t be discouraged! Persistence, collaboration, passion and hard work!